1. Field of the Invention
The present inventor relates to an image forming apparatus mounted with modular parts of image forming means, such as an electrophotographic process unit, and applicable to a laser printer and the like.
2. Description of the Related Art
In modern image forming apparatuses, such as electronic copying machines and printers, parts of image forming means are modular units, including a developing unit, fixing unit, etc. These units can be individually removably mounted in the apparatus body.
If each unit is not mounted, that is, if it not connected electrically or mechanically to the apparatus body, the image forming apparatuses of this type cannot perform normal image forming operations. Accordingly, a sensor is provided for each unit, whereby the attachment of the unit can be detected.
If each unit is furnished with such a sensor, however, the manufacturing costs increase correspondingly, and mounting the sensors require much labor.
In the conventional image forming apparatuses, as described above, a sensor must be provided for each unit to detect the attachment of the unit, so that the apparatus is more expensive as a whole, and more processes are required to assemble the apparatus.